Idenix Pharmaceuticals Inc. (IDIX), a developer of hepatitis C drugs, may shelve experimental treatments currently on hold by U.S. regulators and focus on different versions, Chief Executive Officer Ron Renaud said. The Food and Drug Administration is continuing to assess trials halted last year on two drugs, Cambridge, Massachusetts- based Idenix said today in a slide presentation released ahead of the company’s appearance at the JPMorgan Chase & Co. health- care conference in San Francisco. The FDA put a hold on studies of the company’s IDX184 and IDX19368 after safety issues arose while Bristol-Myers Squibb Co. (BMY) tested a hepatitis C therapy in the same family of nucleotide compounds, called guanosines. Bristol-Myers, based in New York, ended development of its therapy Aug. 23 after it was linked to the death of one patient and kidney and heart concerns in others. “We believe there are significant differences” between Idenix’s drugs and the Bristol-Myers treatment, Idenix said in the slides. The company expects a response from the FDA this quarter, according to the presentation. Idenix is also developing different versions of nucleotides, called uridines, and plans proof-of-concept testing before July, Renaud said in the interview. At the same time, Idenix will test a therapy in a separate class of drugs, a so- called NS5A, with compounds from other companies, to gauge its effectiveness during a 12-week duration.